Synthesis and Characterization of Magnetic Molecularly Imprinted Polymers for the Adsorption of Chlorpyrifos from Aqueous Media

Abstract

Molecular imprinting technology is a specialized technique used to create selective recognition sites within synthetic polymers. It has been employed in the removal of environmental contaminants like pesticides. In this research, a magnetic molecularly imprinted polymer (MMIP) centered on chlorpyrifos as the template molecule was successfully synthesized. Ethyleneglycol dimethacrylate (EGDMA) was the crosslinker, functional monomer used was methacrylic acid (MAA) and initiator was AIBN (2,2′-azobis-isobutyronitrile). The MMIP was successfully characterized using Fourier-transform infra-red (FTIR), scanning electron microscope (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD). The MMIP recorded a high adsorption capacity and selectivity for chlorpyrifos. The MMIP was then used as a dispersive solid phase extraction (D-SPE) adsorbent for isolating and extracting chlorpyrifos from water samples. A gas chromatograph coupled with an electron capture detector (GC-ECD) was used to quantify the extracts. When compared to C-18 solid phase extraction (SPE), the MMIP recorded spiked chlorpyrifos recoveries between 82 and 104% while that for C-18 SPE ranged between 64 and 81%. The limits of quantification (LOQ) and detection (LOD) were 4.91 and 1.62 mg/L respectively.